People insist on feeding the fowl at the pond I like to run in even though there are signs telling them not to. By early summer, ALL of the walkway and large rocks around the pond are covered in fowl doo-doo... by mid-summer there is show much bio-matter growing in the pond it's almost unusable for boats.
Looks like Spring is progressing nicely there, we are just getting the first tulips popping up here in Maryland, no green grass or leaves on anything yet.

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We have a duck problem at our pond also, even though it was purpose-built and the club owns it we cannot keep the damn feeders away and we have a permanent population now. We even treated the pond with a chemical that was supposed to taint the food supply but it didn't work.

There's a thread on RCG somewhere here about a model boat pond being drained and the sides repaired and then water added again... Part of the fun was seeing all the shipwrecks and detritus revealed by the slowly receding water. Some of the boats were reclaimed after years of loss.

Are we certain that that muck is duck feces? Does it not degrade at all or disperse into the water? We need a sick or vomit emoticon...

There's a thread on RCG somewhere here about a model boat pond being drained and the sides repaired and then water added again... Part of the fun was seeing all the shipwrecks and detritus revealed by the slowly receding water. Some of the boats were reclaimed after years of loss.

Are we certain that that muck is duck feces? Does it not degrade at all or disperse into the water? We need a sick or vomit emoticon...

Is there a vid of this?
I would like to see if it so, sounds very interesting.

The trouble with ponds is that they are....ponds. The only drainage is usually via overflow or evaporation, so any solids that find their way in there, stay there. Most of it will be the roughage from fowl, the rest will probably be blown dust that sinks and stays in the water after hitting the surface. Anything soluble will either find its way out via the overflow outlet, or help grow weed.
"My" lake is fed from, and drained into, the sea. It does need to be refreshed regularly by a partial draining and refilling, but these rely on the tides on the other side of the sea wall. If it doesn't get refreshed, should there be a hot summer, it turns into a stagnant mass. In the elder days, it was drained deep and excavated. Nowadays, since the deep drain has vanished, it doesn't.
As to wading in bare feet - let the sight of the pond bottom be a lesson to you!
A few years ago we had a big problem with overpopulation caused entirely by bird feeders. After the RSPB and the council talked, "No Feeding" signs were put up. This worked with all but the most rabid and/or ignorant, the lake has settled to about what it can support, and the park is a much more pleasant place to walk in.

There are no snakes in New Zealand.
I doubt they would be recognized as predators.

That would be an interesting experiment for a biology/ecology class. They could test the hypothesis that recognition as a threat is a learned response. If it is determined that it was learned, it could then explore the mechanisms of teaching. I mean, we all know fish go to school, but what do ducks do for higher education?!?!

If it were an unlearned response, then that would imply that ducks have a genetic memory of some sort, or that they instinctively know of the threat (which might imply an origin outside of NZ, or that NZ once had snakes).

All in all, I think it would be a something to try under the guise of scientific research! If it works, great. If it doesn't, write about it and get government funding to do more model boating